Inserted local redzones.

runtime/szrt_asan.c

 //===- subzero/runtime/szrt_asan.c - AddressSanitizer Runtime -----*- C -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// \brief Provides the AddressSanitizer runtime.
 ///
 /// Exposes functions for initializing the shadow memory region and managing it
 /// on loads, stores, and allocations.
 ///
 //===----------------------------------------------------------------------===//
 
+#include <stdbool.h>
 #include <stddef.h>
 #include <stdlib.h>
 
+static unsigned behind_malloc = 0;
+
 // TODO(tlively): Define and implement this library
 void __asan_init(void) {
-  printf("Set up shadow memory here\n");
-  return;
+  if (behind_malloc)
+    return;
+  printf("set up shadow memory here\n");
 }
 
 void __asan_check(void *addr, int size) {
-  printf("Check %d bytes at %p\n", size, addr);
-  return;
+  if (behind_malloc)
+    return;
+  printf("check %d bytes at %p\n", size, addr);
 }
 
 void *__asan_malloc(size_t size) {
-  printf("malloc() called with size %d\n", size);
-  return malloc(size);
+  if (!behind_malloc)

[Jim Stichnoth, 2016/06/20 19:44:41]

if (behind_malloc == 0)

It's clearer when implicit compares against 0 are just used for booleans.

[tlively, 2016/06/20 22:19:33]

Done.

+    printf("malloc() called with size %d\n", size);
+  behind_malloc++;

[Jim Stichnoth, 2016/06/20 19:44:40]

Generally prefer pre-increment and pre-decrement over the post- versions.

It doesn't make a difference here, for scalars, but I think it's just better to
get in the habit for when increment/decrement is applied to more complex
iterators and the like.

[tlively, 2016/06/20 22:19:33]

Done.

+  void *ret = malloc(size);
+  behind_malloc--;
+  return ret;
 }
 
 void __asan_free(void *ptr) {
-  printf("free() called on %p\n", ptr);
+  if (!behind_malloc)
+    printf("free() called on %p\n", ptr);
+  behind_malloc++;
   free(ptr);
+  behind_malloc--;
 }
+
+void __asan_alloca(void *ptr, int size) {
+  if (!behind_malloc)
+    printf("alloca of %d bytes at %p\n", size, ptr);
+}
+
+void __asan_unalloca(void *ptr, int size) {
+  if (!behind_malloc)
+    printf("unalloca of %d bytes as %p\n", size, ptr);
+}